Stage 1 beginner Free

Linux Fundamentals

Your very first commands. No experience needed — everything is explained as you go.

Lesson steps

1. Welcome
2. Your first command
3. Where am I?
4. Look around
5. Survival kit
6. Hidden files
7. Big files
8. Search for files
9. Search inside files
10. Combine commands with pipes
11. Save output to a file
12. Encoded text
13. Users
14. Reading permissions
15. Changing permissions
16. Your first script
17. Running programs
18. Final challenge: treasure hunt
19. Stage complete

What this stage is

You'll control a real Linux computer by typing short commands — no mouse, no clicking. It runs inside your browser, so there's nothing to install and nothing you do can harm your own computer.

It's split into short steps, in three parts. Each step explains one thing in plain words, shows you exactly what to type, then gives you a small challenge that makes you use it on your own.

Why start with Linux?

Most websites, servers and security tools run on Linux, and people control it by typing commands. Every later stage uses what you learn here.

By the end you'll be able to

• use the shortcuts everyone relies on, and get unstuck when something goes wrong
• move around the computer's folders and read files
• size up a huge file in seconds
• reveal hidden files
• search the whole computer for a file
• find one line among thousands of files
• chain commands together to answer questions, and save the results
• turn scrambled-looking (encoded) text back into words
• see which accounts exist, and who is allowed to read, change or run each file
• write your own script, and see and stop running programs

It ends with a treasure hunt: a trail of clues across the whole computer, solved with everything you've learned.

Learn more (external)

• The Linux Command Line (free book) — A friendly, complete introduction — Parts 1 and 2 cover this stage and more.
• explainshell.com — Paste any command you see online and it explains each part.